Specifiche di progettazione e costruzione per scale e scalini
La norma di riferimento per le specifiche di progettazione e costruzione per scale e scalini è la EN 14122-3.
Di seguito viene riportato un estratto della norma con le indicazioni specifiche per il tipo di applicazione.
4.2 Design and construction for the stair structure and the steps
4.2.1 The structure and the steps shall be designed to satisfactorily resist the foreseeable imposed loads.
The unfactored loads applicable used for the structure of the stair or stepladder in the industriai field can vary. For each application the expected unfactored loads shall be defined. As a minimum the following assumptions for unfactored loads shall be applied in calculations to be considered, but higher values can be necessary. Higher values shall be applied when higher loading is foreseeable:
— for low density pedestrian traffic without load, 1,5 kN/m2;
— for low density pedestrian traffic with load or for high density pedestrian traffic, 5 kN/m2;
4.2.2 Steps shall resist the following minimum unfactored loadings:
— if the clear width < 1 200 mm then 1,5 kN shall be distributed over an area of 100 mm x 100 mm, where one boundary is the leading edge of the nosing applied at the middle of the stair width;
— if the clear width > 1 200 mm then respectively two loads of each 1,5 kN shall be distributed simultaneously over each of the 100 mm x 100 mm, areas applied at the most unfavourable points spaced at intervals of 600 mm where one boundary is the leading edge of the nosing.
The deflection between the structure supporting the steps and the steps under an unfactored load shall not exceed 1/300th of the span of the step or 6 mm, whichever is the lower.